US2639382A

US2639382A - Antenna

Info

Publication number: US2639382A
Application number: US613602A
Authority: US
Inventors: George A Jarvis
Original assignee: US SEC WAR
Current assignee: United States, WAR, Secretary of; US SEC WAR
Priority date: 1945-08-30
Filing date: 1945-08-30
Publication date: 1953-05-19
Anticipated expiration: 1970-05-19

Description

G. A. JARVIS May 19, 1953 I ANTENNA Filed Aug. 50, 1945 INVENTOR.

GEORGE A. JARVIS ATTORNEY.

Patented May 19, 1953 r I g Piv ANTENN George: Jarvis; flambridge Massasiassignbrr by mesner. assignments;; to 'thergUnitedcsstates of Amerioai assrepresented by the Secretary io'-.War

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This 'inven ti'onflrelates o antennas-ifor' h igh preferredi' -ernbodiineritr' only one 'suoh le'nie'n frequency@omniunication systemstand'morena may e sed. For si-n'ipl-i'oity-of'descriptiont'the ticu'larlyito antennas such as'are suitabletforiuse;:= invention -mor'e particularly be "describe asflbeaoonsi hereinafter o'-one- =elehient lo 'althouglfi it 'wi The prinoipal-object ot theinvention issto 'beiindrstoodi tliat=more thantwo or inor e such vide an antenna system adapted to ro'riuo r elements-array a-lso *be titilizdjaocordin'g to thea I mania-oi radiantatenergyihaving: ractically-no invention, depending uporrtheradiation: pattern horizontalm direot-ivity -"but;L.having :*a certairr desire '''lTransmission lineil is -fedAfrOrn bel-GW" I by rnea "ot -fshown and may bejterminatediat 'the ti pper en by' 'absorbin "material shown g'e- For verti'cal direetivityfi the "vertical: :d IpatterrrYHatzin-g. preferably: a maximunwat som'e' smallangle with the liorizontalg. era1lyatl4 r'by"a tuning-plunger l5 or both Another object of the invention .is=-to providet't Riaii'iating elernent ili -oomprises arplurality-of an antennay havingrratradiatiom pattermithat pair *dipol supporting atmsweaon arm-being of the ordr -of quarter wavelength," the ftwo pair extending tin" spacd lpa -i I; "n wn' il l F 1g.-"2-;- tne gtnaoing betwee at tneit point or-con eoti'on'to circular-"in fa horizonal. plane vertical 'respec Inf-general;rthes' present antennai'comprises radiating element adapted to be mounted'riirectly upon an associated ifeeder 'transrnissiorr lin of the enclosed itype xmay' be at: coaxial co ductorror a hollowf pipe nwave guide: Th-'' ele-;

extending way *fjroih in pla" al to the -aixisfof line-' H; "on

arms ahd*'l"7carryifig* ipoleesectionsi l8iaind 19, to: ,..-.-.=Thdipoles' areiexcitediand support" I Afs;will lde-understood?sections 8 edibyiisupportmgamemherstextending 'utwardly I p Similarly? arms fromii hewassociatedf transmission the d it IIdP-I'I 'I' md l'l haveidipole"sections poles beingomounted at thaendsot-the upper 13195,? l9 and 'l9- respectiv'ely;i-'L""Thu" ing memberssz The dipoles mazywbe axiariy oniv in such manner that their projections on a hot zonta'l'iplane. substantial- 1y define a circle with only relatively small interruptions.

The-antenna element describedenerallyabove may be used singlyfas an :jant'ennajJor.iatplurality of such .elements may be arranged on a tram missionlinetoaconstitute a linear array antenn he oateeo n o tm tinto tnezagio Ingthadr wi g'sr I H ofp'ro ration witiiirrthe transmission; line I. max-ins an..elevation tieworranantenn of. As sh in F p i [515 connected toontnar cording to. one 'embodimentof thefg'i'n vention F isi ai'secti'onal View" or 'thei'same alonglltllie linZ -ZOf'F'iE. 1; p V I Fig. 3 is a partial sectio-nal' View similar to suppp tingfbarmi 11 .d s tssataiauettoami; that otrria. 2 showing a modification of thetrinnri I6andis'dirotlyoo td"to anolsiinnjott'edon ventionon .-aareduced scale andw: the outer conductor I3. Thus arm il ll willl b e Fig.4 is a' partial sectional view similar to that -disposed substantially, tangentially.tdfl t lc n, of Fig. 3 showing another modification of the ductorworatanacuteahgl'' bwitli a'linr'ta il invention gent to the outer surface of conductor I3 at the Figs. 1 and 2 illustrate one form of antenna point of connection. system, according to the invention, and show The dipole antenna element I0 is preferably two antenna radiating elements I!) mounted on 50 disposed with the plane through the three dia transmission line ll. Line II is of the coaxial poles horizontal. Also, the dipole sections 3 conductor type having a central conductor 12 I8, I8", [9, l9, and may have a curved: andaspaced outer conductor i3 suitably disposed configuration so that the projection of three in a vertical position. While two elements l0 dipoles, as shown in Fig. 2, on a horizontal plane are illustrated, it willbe understood that, in the 65 substantially defines a circle preferably concentric with line II. This provision, in general, determines the uniform azimuth characteristic. It also reduces the size of the antenna element and permits accommodation of a tubular housing for sealing the device in a weatherproof or pressure-proof manner.

In the modification of the invention shown in Fig. 3, the antenna element In is excited by a hollow wave guide type transmission line. For example a circular wave guide excited in the radial E-vector mode (TM0,1) may be used as the source of excitation. Instead of the supporting arm 16, being connected to a central conductor as described with reference to Fig. 2, a dipole supporting arm 22 extends into wave guide 23 through aperture or slot 24 along the direction of the E- vector for a distance suitable for desired pickup of energy. If desired, a suitable probe or pick-up loop 25 may be carried by or connected to the inner end of arm 22. If desired, the amount of pick-up may-be varied by adjusting the distance which each probe or loop 25 extends into wave guide 23. In fact, if desired, an unsymmetrical pattern may be obtained in the plane passing through the three dipoles by unbalancing the respective distances which arms 22 or probes 25 extend into the wave guide 23. As will be understood, this mean of excitation may also apply to the coaxial conductor type transmission line, as described with reference to Fig. 2. Thus arms l6, l6 and I9" need not be directly connected to central conductor l2 but may extend the desired distance into the space in the coaxial line between the central and outer conductors l2 and I3, for capacitive coupling.

In order to support arm 22 of Fig. 3 or arm it of Fig. 2 when the latter is not directly connected to the central conductor l2, it is necessary to provide supporting means. One such means is shown in Fig. 4 and comprises a dielectric member 26 in place of slots or apertures 24 or of Figs. 2 and 3 and secured to the outer wall of the wave guide 23 or outer conductor of the coaxial line. dielectric member 26 has an aperture therethrough, which may be threaded, for receiving arm 22 or [6 whereby arm 22 or I6 is supported by the dielectric member and is insulated from the outer conducting wall of the wave guide 23 or of coaxial line H.

It will be understood that the antenna, according to this invention, in its contemplated vertical position with the dipoles uniformly spaced about the transmission line and uniformly excited, is adapted to radiate energy in a pattern which is substantially circular in a horizontal plane (uniform in azimuth) and in a substantially uniform and symmetrical pattern in a vertical plane.

While there has been described what is at present considered preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the spirit ofthe invention.

What is claimed is:

1. An antenna construction, adapted for use The with an enclosed transmission line, for high frequency electromagnetic energy, comprising three curved dipoles uniformly spaced about said line, each of said dipoles comprising a pair of spaced dipole sections lying in a plane perpendicular to the longitudinal axis of said line, and means for supporting and exciting each of said dipoles, each of said means comprising a pair of spaced parallel supporting arms having a length substantially equal to a quarter of the wavelength of the exciting energy, and extending outwardly from said line, one of said dipole sections being electrically connected and carried at the outer end of each of said supporting arms, one of each pair of supporting arms being connected to the outer conductor wall of said line at a point adjacent one of three apertures and extending substantially tangentially from said outer conductor, the other of each pair of supporting arms extending substantially radially of said line through the corresponding aperture in said Wall and into the region of propagation within said line, the inner end of each of said radially extending supporting arms being electrically coupled to said energy in said line whereby said dipoles are excited by said energy.

2. An antenna construction as claimed in claim 1 wherein each of said dipole sections is so disposed that the curved configuration of said three dipoles projected on a plane perpendicular to the axis of said line substantially defines a circle about said axis.

3. An antenna construction as claimed in claim 1 adapted for use with a coaxial cable transmission line having a central conductor and a spaced outer conducting wall, wherein the radially extending supporting arms have their inner ends electrically connected to and carried on said central conductor.

4. An antenna construction as claimed in claim 1 adapted for use with a hollow pipe wave guide transmission line, wherein coupling means are provided at the inner ends of the radially extending arms of said pairs of supportin arms whereby said dipoles are excited by the energy in said line and wherein dielectric means are provided for supporting said radially extending arms on said wave guide while insulating said radially extending arms from the Wall of said wave uide.

GEORGE A. JARVIS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,166,750 Carter July 18, 1939 2,289,856 Alford July 14, 1942 2,298,429 Bailey Oct. 13, 1942 2,413,085 Tiley Dec. 24, 1946 2,485,920 Riblet Oct. 25, 1949 FOREIGN PATENTS Number Country Date 114,368 Australia Dec. 9, 1941